1. Field of the Invention
The present invention relates to liquid discharge apparatuses and a method for manufacturing such liquid discharge apparatuses.
2. Description of the Related Art
Conventionally, ink jet heads jetting liquid drops of ink from nozzles are known as liquid discharge apparatuses jetting a liquid. There is known ink jet heads which include a channel structure (channel unit) in which ink channels are formed to include a plurality of nozzles, and a piezoelectric actuator (actuator unit) joined to the channel unit.
The channel unit has a plurality of pressure chambers in respective communication with the plurality of nozzles. The piezoelectric actuator has four piezoelectric layers (piezoelectric sheets) arranged to cover the plurality of pressure chambers, a plurality of individual electrodes arranged on one surface of the upmost piezoelectric layer to face the plurality of pressure chambers respectively, and a common electrode arranged on the other surface of the upmost piezoelectric layer. Further, in the upper surface of the upmost piezoelectric layer, grooves are formed to correspond respectively to the plurality of pressure chambers. In more detail, in a planar direction of the piezoelectric layers, two grooves are formed in such a position as to interpose each pressure chamber therebetween.
In the piezoelectric actuator, when a drive voltage is applied between an individual electrode and the common electrode, contraction in the planar direction occurs in such a portion of the upmost piezoelectric layer as interposed between the individual electrode and the common electrode, thereby causing the four Piezoelectric layers to deform as projecting toward the corresponding pressure chamber. Because this deformation of the piezoelectric layers also changes the volume of the pressure chamber, the pressure on the ink inside the pressure chamber rises, thereby jetting the ink from the nozzle.